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Other - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 08, 2017
Feb. 15, 2017
Mar. 31, 2017
Mar. 31, 2016
Other [Line Items]        
Quarterly dividend declared     $ 0.0425 $ 0.0425
Cash dividend paid     $ 613,000 $ 594,000
Dividend Declared        
Other [Line Items]        
Dividend declaration date Mar. 08, 2017 Feb. 15, 2017    
Quarterly dividend declared $ 0.0425      
Dividend payable date May 15, 2017      
Dividend declared, date of record May 01, 2017 Feb. 01, 2017    
Dividend payable     $ 680,000  
Cash dividend paid   $ 613,000